Vibration generating device for vibratory machine

ABSTRACT

A vibration generating device for a vibratory machine has a reversible electric motor with at least two eccentric weights on the opposite ends of the shaft thereof, the position of which is automatically changeable upon reversal of the direction of rotation of the motor. The weights act during rotation of the motor to cause the machine to effect different vibratory motion depending on the direction of rotation of the motor.

United States Patent Kobayashi [4 1 Sept. 12, 1972 [54] I VIBRATIONGENERATING DEVICE [56] References Cited FOR VIBRAT Y A 0R M CHINE UNITEDSTATES PATENTS [72] Inventor: Hisunine Kobayashi, Nagoya, Japan2,857,535 10/1958 Kroeckel et al. ..3l0/8l 1 Asslsnw Kebushiki KnishShikishiml e- 2,ss4,s94 9/1958 Philippovic ..3 10/81 x tomNagoya, Japan3,097,537 7/ 1963 Peterson ..74/6l 22 il Nov. 2 1970 3,572,641 3/1971Peterson ..74/87 X [21] Appl. No.: 86,170 FOREIGN PATENTS ORAPPLICATIONS LS. D. l 3 l Great 3 l [62] Division of Ser. No. 787,534,Dec. 27, 1968, Primary Examiner-D. F. Duggan abandoned.Attorney-Wenderoth, Lind & Ponack [30] Foreign Application Priority Data[57] ABSTRACT g 3 Japan A vibration generating device for a vibratorymachine 2 1 6 Japan "43/322 has a reversible electric motor with atleast two eccen- May 10, 1968 Japan ..43/3 8696 tric weights on theopposite ends of the shaft thereof the position of which isautomatically changeable [52] US. Cl. ..3l0/8l upon reversal of thedirection of rotation of the moton [51] Int. Cl. ..H02k 7/06 The weightsact during rotation f the motor to cause [58] Field of Search ..3l0/80,81; 74/26, 61, 87;

759/DIG. l, DIG. 42, DIG. 43

the machine to effect difierent vibratory motion de- 1 pending on thedirection of rotation of the motor.

3 Claims, 8 Drawing Figures PATENTEDsEP 12 I972 SHEET 1 0f 3 PIC!INVENTOR HISAM INE KOBAYASH] BY wed/5,4; F

ATTORNEYS PATENTEU E 12 I97? 3.691. 409

SHEET 2 BF 3 INVENTOR HISAMINE KOBAYASHI ATTORNEYS PATENTED SEP 12 m2INVENTOR H ISA MINE KOBAYAS HI FIGS BY flw dw /r Z 64 ATTORNEYSBACKGROUND OF THE INVENTION AND PRIOR ART The present invention relatesto a vibration generating device for a finishing machine or the likehaving automatically adjustable eccentric weights.

Vibratory machines of several different types having vertically orhorizontally oriented motors are known in the art. In prior artfinishing machines, the vibration generating device for said machineshas a motor means with eccentric weights clamped on the shaft thereof.Any adjustment of the position of the eccentric weights is usuallyperformed by hand and is a difficult and timeconsuming process.

As is well known in the art, the production of linear motion and orbitalmotion in a mass confined in an annular chamber is dependent chieflyupon the relative positioning of eccentric weights on the shaft of themotor for producing such motion. It is sometimes desirable for themachine to have two kinds of vibration. For instance, different kinds ofvibration are preferred in finishing and separation. Orbital motion ofthe mass is preferred for the finishing operation and progression of themass linearly along the finishing chamber is preferred for theseparating operation. Another instance in which different kinds ofvibration are preferred is in grinding and polishing. In ordinaryprocessing, workpieces are at first roughly finished and then polished.In prior art finishing machines, not only are two sets of machinesnecessary for the two kinds of work, but also auxiliary machines arenecessary, that is a screening machine and transportation apparatus.

OBJECT AND BRIEF DESCRIPTION OF THE INVENTION It is accordingly aprimary object of the present invention to provide a vibrationgenerating device wherein two kinds of vibration are providedautomatically by reversal of the direction of motor rotation.

This object is achieved by the provision of a vibration generatingdevice comprising a motor having at least one and preferably twoautomatically adjustable eccentric weights, preferably one on each endof the motor shaft. The position of at least one of said eccentricweights is changed automatically to predetermined phase angle dependingon the direction of the rotation of said motor means.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be furtherdescribed, by way of example only, with reference to the accompanyingdrawings in which:

FIG. I is a side elevational view of vibration generating deviceaccording to the invention, with parts illustrated in section and partsbroken away;

FIG. 2 is a plan view of the device shown in FIG. 1;

FIG. 3 is a fragmental sectional view taken on line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 3, illustrating an automaticallychangeable eccentric weight preferably to be mounted on the lower end ofthe motor shaft;

FIG. 5 is a fragmental side elevational view of the device shown in FIG.4;

FIG. 6 is a diagrammatic view for explaining the operation of the deviceshown in FIGS. 3 to 5;

FIG. 7 is a side elevational view of a vibratory finishing apparatushaving a vibration generating device according to the invention mountedtherein; and

FIG. 8 is a plan view of the apparatus shown in FIG. 7 indicating themovement of the mass.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to theaccompanying drawings for a better understanding of the invention. Thevibration generating device 28 will be described with reference to FIGS.1 to 6. The unit 28 comprises a reversible electric motor 44 having amounting flange 46 rigidly secured to a vibratory machine. The motor 44has an output shaft 50 projecting beyond each end of the motor housing.Each of the projecting end portions of the shaft 50 is stepped and isprovided with at least one eccentric weight 52 or 54a. The eccentricweight 52 or 54a is disposed on the motor shaft 50 so as to be rotatableabout the axis thereof. To this end, an exchangeable sleeve 58 is keyedto the shaft end by a key 56 and said sleeve is provided with acircumferential groove 60 extending a predetermined distance around theperiphery of the sleeve so as to subtend a predetermined angle, as shownin FIGS. 3 and 4. The grooves can have a circumferential length equal toor different from each other. The eccentric weight 52 or 54a is mountedon the associated sleeve 58 by having the hub 62 thereon rotatablyfitted onto the sleeve and a control pawl 64 on the hub extending intothe associated groove 60.

Because the eccentric weights are rotatable with respect to the sleeve,when the motor is rotated in the direction of the arrow 68, i.e.,clockwise as viewed in FIGS. 3 and 4, the inertia of the weights causesthem to remain still while the shaft 50 and sleeve 58 turn within thehubs 62 until the ends of the grooves on the sleeves 58 engage thecontrol pawls 64 to drive the weights. The respective weights takepositions 52.1 and 54.1 respectively. This means that the weights lag byangles of a or 0 respectively with respect to the reference positions asshown in FIGS. 3 and 4. In the same way, when the motor is rotated inthe direction of the arrow 69 i.e. counterclockwise as viewed in FIGS. 3and 4, the weights lag by angles b or d respectively with respect to thereference positions. If desired, both the weights can be mounted on theshaft 50 for displace ment about the axis thereof. That is, weight 52can be mounted on the upper end of the shaft and weight 54a can bemounted on the lower end of the shaft, in which case the differencebetween the angles of the two weights, i.e., angle (a-c), will be therelative displacement of the weights. Alternatively the upper weight canbe movable and the lower weight can be fixed, as weights 52 and 54 shownin FIG. 1. Either of the weights 52 or 54 can be fixed on the shaft 50.In order to fix either one of the upper or lower eccentric weights 52and 54 on the shaft 50, the weight can be stepped and a set screw 66extend through the upright portion thereof between the steps, as shownin FIG. 5.

In order to prevent the weight from falling from the shaft, the same ispreferably sandwiched between two washers 68 and 68 and then secured onthe shaft 50 by a set screw 70 as shown in FIG. 5. Also as shown in FIG.5 one or more additional weights 72 can be secured to the eccentricweight by screws in order to adjust its mass.

When the lower weight is rotatably disposed on the associated sleeve 60as shown in FIG. 4, while the upper weight is fixedly disposed, rotationof the motor 44 in direction of the arrow 68, i.e., clockwise as viewedin FIGS. 3 and 4, will cause the upper weight 52 to remain at itsposition 52 as shown in FIG. 3 fixed with respect to the rotating motorshaft, while the lower weight 54a will move to the position 54-1, withthe result that the upper weight 52 leads the lower weight 54 by anangle 0 as shown in FIG. 6. When the motor is rotated in thedirection ofthe arrow 69 or in the counterclockwise direction, the upper weight 52remains at its position 52 as shown in FIG. 3, fixed to the rotatingmotor shaft, and the upper weight 52 will lead the lower weight 54a byan angle d" as shown in FIG. 6.

On the contrary, when the upper weight 52 is rotatably disposed on theassociated sleeve 58, as shown in FIGS. 1 and 3, while the lower weight54 is fixed on the associated sleeve 60, as shown in FIG. 1, then thelower weight 54 remains at its position 54 as shown in FIG. 6 fixed withrespect to the rotating motor shaft, and the lower weight 54 leads theupper weight 52 by angle ofa" or b depending on the direction ofrotation of the motor. Alternatively, when both weights are rotatablymounted on the motor shaft, e.g., with upper weight 52 of FIG. 3 andlower weight 54a of FIG. 4, the upper weight lags behind the lowerweight a-c or b-d", depending on the direction of rotation of the motor.

It is to be understood that the angle between the weights can be variedby changing the length of either groove 60. To this end, the motor shaftcan have stops thereon and either the upper or lower sleeve or both canhave a circumferential groove having any desired length.

Referring now to FIGS. 7 and 8, as one example of its use the vibrationgenerating unit 28 is mounted on a self-separating vibratory finishingapparatus. The finishing apparatus has a hollow pedestal 10 disposed ona foundation (not shown) on a plurality of short legs 12 of any suitableshock absorbing material such as rubber and fixed to the bottom thereof,and a cover 14 enclosing a plurality of helical springs 16 fixed at oneend to the top of the pedestal l0 and disposed at substantially equalangular intervals around a central axis of said pedestal. A horizontalbase flange 18 is rigidly secured to the other ends of the helicalsprings 16.

Rigidly secured to the base flange 18 is a vibratory finishing trough 22in the form of a toroid. A cylindrical housing 26 extends through thehollow central portion of the trough 22 and is sealed thereto, andextends through the base flange 18. The said vibration generating deviceaccording to the invention is fixed to the lower end portion of theinterior of the cylindrical housing 26.

As shown in FIG. 8, a sieve 30 is fixedly secured on the top face of thetrough 22 so as to fully cover one portion thereof. At one edge of thesieve 30, a rockable flap 40 is pivotally mounted on a rod 38. The flap40 has a horizontal position in which it can be fixed by any desirablemeans (not shown in the figure) and where it is inoperative, and apendent position in which it be tilted at a predetermined angle to thehorizontal and extends down into trough 22 where it is operative.

The vibration generating unit 28 is energized to forcedly vibrate thetrough 22 to impart a motion to a mass in the trough, which massincludes workpieces and abrasives. The vibratory motion has two components, one of which causes the mass to move in an orbital path asshown by the arrows 76 and the other of which causes the mass toprogress linearly in a direction determined by the direction of rotationof the motor 44.

As is well-known in the art, the production of linear motion and orbitalmotion in a mass confined in a chamber is dependent upon many factorsincluding the center of mass of the suspended apparatus, the position ofthe motor, and especially on the relative placement of eccentricweights. By calculation and experiments, an optimum placement ofeccentric weights can be obtained for carrying out a finishing andseparation operation, when the dimension of the trough, weight andvolume of the mass in the trough, position of the motor, shape and massof the eccentric weights and speed of rotation of the motor are known.For finishing, the mass must be moved in an orbital path with slightlinear motion which is opposite to the direction of rotation of themotor shaft as shown by arrows 76 and 77 in FIG. 8. For separation, themass must be moved linearly with a slight orbital motion as shown byarrows 78 and 88 in FIG. 8. For example, in the embodiment shown inFIGS. 7 and 8, clockwise rotation of the motor shaft is used for thefinishing operation, the advance angle of the upper weight beingautomatically adjusted so as to be 15 to 30 by the structure asdescribed above, and the mass effects a helical motion 76 and is shiftedin the direction of the arrow 77, i.e., counterclockwise as viewed inFIG. 8. On the other hand, counterclockwise rotation of the motor shaftis used for the separating operation, the advance angle of the upperweight being automatically adjusted so as to be 70 to 105 degrees by thestructure as described above and the mass effects a helical motion 78and 88 and is shifted in the direction of the arrow 79, i.e., clockwise.The progressing mass causes the flap 40 to be rotated downwardly fromits horizontal position about the axis of the rod 38 when the flap isreleased by any suitable means (not shown). Then the stream of the massexerts a dynamic force upon the pendent flap tending to cause it to sinksmoothly into the flowing mass until the flap is stably engaged at itsperiphery against the internal surface of the wall of the trough 22.Thus the flap 40 blocks the stream of the mass.

Under these circumstances the successive portions of the flowing masspushing against the flap 40 forcedly ascend the flap and are transferredto the sieve 30 where the finished workpieces are separated from theabrasives and then delivered in the direction of the arrow 34a through adelivery port 34 to the succeeding processing section (not shown). Theabrasives fall through the sieve 30 into the trough 22. A flash gate 90is caused to descend into the trough 22 during the separating operationto aid the flap in giving the mass upward motion.

When the separating operation is finished, the motor is again reversedand the flash gate is lifted by any suitable means (not shown). Then,the direction of flow of the mass is also reversed and the mass pushesthe flap 40 upwardly to its inoperative position. The fiap is fixed atits horizontal position, unfinished workpieces are put in the trough andthe finishing operation begins.

As can be seen from the above description, workpieces can be easilyseparated from the abrasives after completion of vibratory finishing andthe finishing operation can be easily restarted after completion of theseparating operation by using said vibration generating device and byreversing the motor.

Although the invention has been particularly described and illustratedwith respect to its application to a self-separating vibratory finishingmachine, numerous other applications requiring two kinds of vibration ina vibratory machine will be immediately apparent. For example, the samevibration generating device can be used for grinding mills and afinishing machine with a vertical or horizontal motor axis in which twokinds of vibrating conditions are necessary.

I In a finishing machine, fine polishing can be carried out after roughfinishing in one machine by reversing the motor when the vibrationgenerating device according to the present invention is used. Otherwise,two sets of machines, separating machines and transportation means arerequired.

It is to be understood that the invention is not limited to the exactdetails of construction, operation or exact materials or embodimentsshown and described, as obvious modifications and equivalents will beapparent to one skilled in the art, and the invention is therefore to belimited only by the scope of the appended claims.

What is claimed is:

l. A vibration generating device for vibrating a vibratory machine togive two kinds of vibratory motion to said machine, comprising areversible motor means having a rotor, at least two stops on said rotorspaced from each other in a direction around said rotor, and a pair ofeccentric weights on said rotor, at least one of said weights beingmovably mounted for free angular movement around the axis of rotation ofsaid rotor between said stops, said one weight rotating due to itsinertia when said rotor rotates in one direction until it abuts one stopand rotating due to its inertia when said rotor rotates in the otherdirection until it abuts the other stop, said stops being at positionswhich when said one weight is against the one stop it leads the otherweight by a predetermined angle during rotation of the motor means inone direction of rotation and when said one weight is against the otherstop it leads the other weight by a predetermined angle during rotationof the motor means in the other direction, whereby reversal of thedirection of rotation of said motor means causes said one weight to moveautomatically from one stop to the other stop for switching of thevibratory motion in said vibratory machine.

2. A vibration generating device as claimed in claim 1 wherein the othereccentric weight is fixed to said rotor of said motor means and only theone eccentric weight is freely movably mounted on said rotor.

3. A vibration generating device as claimed in claim 1, wherein both ofsaid eccentric weights are freely movably mounted to said rotor and twofurther stops are provided on said rotor between which the othereccentric weight is movable, said further stops being spaced around therotor a different distance from the firstmentioned stops whereby saidweights are responsive to rotation of said motor means to move angularlythrough predetermined different angles about the axis of rotation of therotor in each direction of rotation thereof.

1. A vibration generating device for vibrating a vibratory machine togive two kinds of vibratory motion to said machine, comprising areversible motor means having a rotor, at least two stops on said rotorspaced from each other in a direction around said rotor, and a pair ofeccentric weights on said rotor, at least one of said weights beingmovably mounted for free angular movement around the axis of rotation ofsaid rotor between said stops, said one weight rotating due to itsinertia when said rotor rotates in one direction until it abuts one stopand rotating due to its inertia when said rotor rotates in the otherdirection until it abuts the other stop, said stops being at positionswhich when said one weight is against the one stop it leads the otherweight by a predetermined angle during rotation of the motor means inone direction of rotation and when said one weight is against the otherstop it leads the other weight by a predetermined angle during rotationof the motor means in the other direction, whereby reversal of thedirection of rotation of said motor means causes said one weight to moveautomatically from one stop to the other stop for switching of thevibratory motion in said vibratory machine.
 2. A vibration generatingdevice as claimed in claim 1 wherein the other eccentric weight is fixedto said rotor of said motor means and only the one eccentric weight isfreely movably mounted on said rotor.
 3. A vibration generating deviceas claimed in claim 1, wherein both of said eccentric weights are freelymovably mounted to said rotor and two further stops are provided on saidrotor between which the other eccentric weight is movable, said furtherstops being spaced around the rotor a different distance from thefirstmentioned stops whereby said weights are responsive to rotation ofsaid motor means to move angularly through predetermined differentangles about the axis of rotation of the rotor in each direction ofrotation thereof.